<local:RssReaderViewModel 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"       
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:RssReader" >
    <local:RssReaderViewModel.Feeds>
        <local:FeedViewModel 
            FeedName="design one" 
            FeedUrl="Maecenas praesent accumsan bibendum" />
        <local:FeedViewModel 
            FeedName="design two" 
            FeedUrl="Dictumst eleifend facilisi faucibus" />
        <local:FeedViewModel 
            FeedName="design three" 
            FeedUrl="Habitant inceptos interdum lobortis" />
    </local:RssReaderViewModel.Feeds>
</local:RssReaderViewModel>